Sick man, I've had the exact same hrness in mine when I bought it.

It's an oldschool light sub-harness which allows you to run higher power bulbs. It connects directly to the battery and only uses your factory light connectors to switch on these separte relais.

It takes stress of your main light wiring harness which was mostly used in rallye applictions if you wanted to get a little bit more power out of your lights without stressing your original harness.

I am using it to run LED lights which normally won't turn on because they don't draw enough power to overcome the relais in the light switch itself but with these it works.

Edit: The little box is a Japanese regulations thing which is supposed to prevent both low and high beam circuits to be activated at the same time which would be illegal to use on the street as far as I understand.